1. Field of the Invention
The present invention relates to a portable computer, and more particularly, to a touch pad device that is used in a portable computer as an input device.
2. Description of the Related Art
Portable computers such as notebook computers generally employ a touch pad device or pointing stick as a pointing device that can be used instead of a mouse while they are carried. FIG. 5 shows a portable computer equipped with a related art touch pad device.
As shown in FIG. 5, the portable computer is mainly composed of a main body 1 and a display unit 3. The display unit 3 can be folded onto a top surface of the main body 1 or unfolded at a predetermined angle as shown in this figure, because an end of the display unit is hinged to a rear end of the main body 1. The display unit 3 includes a display 3′ for which a liquid crystal display (“LCD”) may be used.
A key deck 5 is formed on the top surface of the main body 1. A plurality of keys 7 are arranged on the key deck 5. An armrest 9, onto which hands of a user are placed when typing using keys 7, is formed at a front end of the main body 1. Further, a touch pad device 10 is provided at the center of the armrest 9.
The configuration of the touch pad device 10 of FIG. 5 is shown in an exploded view in FIG. 5a. The key deck 5 is provided with a pad window 11 and a button through-hole 12. The pad window 11 is generally formed to have a rectangular shape, and the button through-hole 12 is formed ahead of the pad window 11.
A touch pad 13 is securely seated into the pad window 11 from below the key deck 5. The touch pad 13 senses the contact of hands to receive information on the positions where a user intends to point. The touch pad 13 is provided with a cable 14 and a connector 15 in order to send signals to the CPU of the portable computer.
A touch pad housing 16 is provided to fix the touch pad 13 to the key deck 5. The touch pad housing 16 is formed with a seated portion 16′ on which the touch pad 13 is securely seated. A lower edge of the touch pad 13 is securely seated on the seated portion 16′.
The touch pad housing 16 is further provided with fastening bosses 17 used to mount the touch pad housing 16 to the key deck 5. Each fastening boss 17 is formed with a fastening hole 17h through which a screw is fastened to the key deck 5.
Buttons 18 are provided at the front end of the touch pad housing 16, which corresponds to a position where the button through-hole 12 is formed. The buttons 18 function to select the position information received through the touch pad 13.
However, the aforementioned prior art has the following problems:
First, since the touch pad housing 16 and the screws are used to allow the touch pad 13 to be fastened into the pad window 11 of the key deck 5, there are problems in that the total number of parts and the man-hours required for assembly are increased.
Further, since the touch pad housing 16 is fastened to a bottom surface of the key deck 5 with screws, there is inconvenience in that the key deck 5 must be separated from the main body 1 in order to perform maintenance on the touch pad 13.
Furthermore, since two screws are used to mount the touch pad housing 16 to the key deck 5, the touch pad housing 16 is not brought into close contact with the bottom surface of the key deck 5 as a whole. Therefore, there is a problem in that electromagnetic (EM) waves generated in the main body 1 leak to the outside through a gap defined between the touch pad housing 16 and the bottom surface of the key deck 5. To solve this problem in the related art, a copper tape may be applied to the touch pad housing 16 and the key deck 5. However, this requires additional man-hours for the assembly and the production costs are increased.